1. Field of the Invention
This invention relates generally to attachments for earth moving vehicles, such as tractors, and more particularly to a box blade attachment having a rotatable closure blade.
2. Brief Description of the Prior Art
Conventional box blade attachments for use on tractors consist basically of a rectangular frame enclosed on four sides and open at the top and bottom. A scraper blade extends along the bottom edge of the rear wall to scrape dirt into the frame as the tractor pulls the box blade along the surface of the ground. In addition to scraping operations, the dirt contained in the box blade may be leveled out to fill low spots as it passes over the surface of the ground.
The conventional box blade cannot be lifted for transporting dirt which has been collected because it has no bottom. To transfer dirt to another location, the tractor must drag the box blade filled with dirt along the surface of the ground to the other location, sometimes destroying everything in its path.
There are several patents which disclose various earth moving and transporting attachments for tractors, some of which are provided with closure means.
Rapp, U.S. Pat. No. 2,189,222 discloses a scraper bucket having an open rear end and a movable closure.
Bain, U.S. Pat. No. 2,558,531 discloses a scraper bucket having a retaining apron which can be moved to a position closing the scraper to form a bowl.
Lindquist, U.S. Pat. No. 2,565,384 discloses a scraper assembly having a power actuated scraper portion for moving earth into a supporting bucket.
Lewis, U.S. Pat. No. 3,319,367 discloses a bottom unloading scoop attachment for mounting on a tractor three point hitch.
Hare, U.S. Pat. No. 4,103,796 discloses an apparatus for attaching bucket or scoop onto a conventional three point hitch. The bucket is hydraulically actuated between a filling position and a dumping position.
The prior art in general, and none of these patents in particular, disclose an open bottom box blade having a rotatable closure blade for scraping and moving earth from one location to another.